Adjustable depth control hydraulic cylinder stop mechanism



Nov. 22, 1960 G. L. HERSHMAN 2,960,969

ADJUSTABLE DEPTH CONTROL HYDRAULIC CYLINDER STOP MECHANISM Filed Feb. 12, 1958 3 Sheets-Sheet 1 J'JVVENTOE 6020 ON L. HB$HM4N MOW NOV. 22, 1960 HERSHMAN 2,960,969

ADJUSTABLE DEPTH CONTROL HYDRAULIC CYLINDER STOP MECHANISM Filed Feb. 12, 1958 3 Sheets-Sheet 2 Dl/E'NTCDE 6 eaozv amazes/1 444 Nov. 22, 1960 HERSHMAN 2,960,969

ADJUSTABLE DEPTH CONTROL HYDRAULIC CYLINDER STOP MECHANISM Filed Feb. 12, 1958 3 Sheets-Sheet 3 yzg 9a 92 9 JM/ENme 69 Gozoo/v LJ-JEEsHMAN H/TOENE United States Patent @iiioe Patented Nov. 22, 1960 ADEUSTABLE DEPTH CONTROL HYDRAULIC CYLENDER T9? MECHANISM Gordon 1.. Hershman, Chicago, 111, assignor to International Harvester tlompany, (Zinc-ago, 313., a corporation of New Jersey Filed Feb. 12, 1953, Set. No. 714,885

9 Claims. c1. 1121-35 This invention relates to depth control apparatus as employed in connection with a ground working implement adapted to operate with a vehicle, such as a tractor, but, more specifically the invention is concerned with adjustable, presettable means motivatable by vertical movement of the implement for controlling the operation of an associated hydraulic actuating system.

Heretofore, a great variety of hydraulic cylinder stop mechanisms have been proposed for use with hydraulic ram devices and the present invention is directed to an improvement in mechanisms of this character. It is a primary feature of the present invention, therefore, to provide an improvement in presettable means for controlling the depth at which an earth working implement is operated.

Another important object'is to provide an actuating mechanism, responsive to the movement of a piston in a hydraulic cylinder, for controlling the flow of fluid pressure in said hydraulic cylinder.

Another object is to provide improved restricting means the operation of which initiates a control valve means in a hydraulic actuating circuit whilesaid control valve interrupts the flow of fluid pressure to stop the movement of a piston in a hydraulic ram actuated by said circuit, the operation of said restricting means being responsive to movement of the piston in s aid ram.

A further object is to provide a combination-indicator and stop valve mechanism for a hydraulic circuit, and wherein the indicator is presettable to effect actuation of the stop valve responsive to a predetermined amount of movement of a piston in a hydraulic cylinder connected in said circuit.

A more specific object is to provide a sleeve-type restricting means selectively presettable to close and substantially actuate a control valve in a hydraulic circuit upon the accomplishment of a predetermined amount of movement of a piston in a'ram cylinder assembly connected in said circuit.

Another specific object is to provide a combination indicator and adjustable valve mechanismfor a hydraulic circuit wherein the valve mechanism is normally biased to an open position that'permits the flow of fluid pressure in the circuit, and is movable, by motion-transmitting means responsive to movement of a ram cylinder assembiy connected in the circuit, to a closed position that restricts the flow of fluid pressure in the. circuit.

The present invention includes-thenovel constructions, arrangements, and devices that will subsequently be described and claimed for accomplishing the above noted objectstogether with such other objects as-will be. apparent from the following description of apreferred embodiment of the invention, as illustrated, with reference to the accompanying drawings in which:

Figure l is a schematic diagram or" a hydraulic system incorporating therein a combination indicator and a stopvalve mechanism fashioned accordingto the present invention, and showing certain of the elements thereof in section and other elements in broken or cut-away fashion;

Figure 2 is a vertical, longitudinal sectional view, in enlarged dimension, through the control valve component of the hydraulic system, the elements thereof being shown in the positions assumed when said valve is in neutral;

Figure 3 is a view similar to Figure 2, but showing the elements of the control valve operatively conditioned for transmitting fluid pressure into one end of a hydraulic ram in the hydraulic system;

Figure 4 is a fragmentary sectional view, similar to Figures 2 and 3, showing, in enlarged dimension, the relief valve element of the control valve conditioned to its opened position;

Figure 5 is a horizontal sectional view of the indicator and stop-valve mechanism taken on line 55 of Figure 1;

Figure 6 is a fragmentary vertical sectional View of the combination indicator and stop-valve mechanism and showing the position of the elements therein when said stop-valve has been manipulated to its operatively closed position; and

Figure 7 is a fragmentary, vertical sectional view, in enlarged dimension and rotated from the position showing in Figure 6, and showing one end of the proposed cut-off or stop-valve mechanism.

Referring now to the drawings, where there is depicted a preferred form of the invention, it will be noted that the illustrated embodiment includes a hydraulic circuit or system having a ram cylinder 11 that is connected by a conduit 11 to the proposed restrictor stop-valve device, indicated generally by the reference numeral 12, and by a conduit 13-to a control valve unit 14. Another conduit 15 is connected between the cut-off valve 12 and the control valve unit 14, while a conduit 16 connects said control valve with a reservoir or sump indicated at 17, and a conduit 18 connects the control valve With a hydraulic pump 19 the opposite side of which is connected to the reservoir 17 by a conduit 26 It will be understood, of course, that the pump 19, which may be of any suitable well known conventional type for providing fluid pressure, will be suitably connected to a power unit such as a vehicle engine (not shown) and operatively driven thereby.

The hydraulic work cylinder or ram unit 10, being generally conventional in construction, will be seen to comprise a housing or body-like cylinder 211 closed at opposite ends by the closure cap-like members 22 and 23, and having a piston 24 slidably mounted therein with a connecting rod 25 aflixed thereto and extending from said piston slidably through the end cap 23. A connecting ring-like eyelet 26 on the free end of said connecting rod is adapted for connecting the ram unit to the drawbar linkage (not shown) that is usually provided on a tractor vehicle, as is well understood, while the opposite end cap 22 may be fashioned with a mounting ring or lug 27 for attaching the respective end of the ram unit to a suitable supporting portion of a tractor frame or chassis (not shown). It will be appreciated, of course, that suitable pins or shaft'like retainers or fasteners, such as indicated at 26a and 27a, will be provided for suitably affixing the eyelet 2 6 and the lug 27 to the respective connecting or supporting portions of the vehicle, according to general practice in the art.

The control valve'l may be any suitable well known manually operable:hydraulic circuit control valve provided with an automaticrholdand release means and wherein the release maybe triggered by arise in pressure within the circuit attendant the interruption or restriction of fluid flow therein. .Valves of this type are well known and conventional, and onev such valve, that functions in the manner desired, is shown in the U.S. Patent 2,5 94,664, issued April 29, 1952, to C. B..Livers et al. The valve disclosed therein is:fash-.ioned with a manuallyactuable handle or lever 28 and is provided with an inlet or pressure port opening 29, an outlet or discharge port opening 30 and a pair of work port openings 31 and 32. A body member 33 having a central bore 34 thereinfis adapted for slidably receiving a piston 35 which is manually operative by the handle 28 .for interconnectingthe various ports in order to direct fluid flow therethrough as desired. In the neutral position of the valve, shown in Figure 2, the inlet port 29 is established in free fluid communication with the outlet port 30, while lands 35a and 35b on the piston 35 are positioned to block or close off the work ports 31 and 32 thus restricting movement of fluid pressure into and out of the associated hydraulic ram unit 10. Upon movement of the piston 35 to the right, for instance, as shown in Figure 3, a land 35c thereon is moved into blocking relation between the inlet and outlet ports 29 and 30, respectively, to interrupt the free flow of fluid between these ports, while lands 35a and 35b are simultaneously moved clear of the working ports 31 and 32, respectively, permitting fluid communication by way of a radial passage 36, a longitudinal passage 37, and a radial passage 38 in the piston, between said latter work port and the inlet port 29 to effect the transmission of fluid pressure into the upper end of the ram unit 10, while at the same time permitting fluid to be exhausted from the opposite end of the cylinder thereof by way of work port 31 which attendantly is established in communication with outlet port 30.

. The piston 35 is yieldably held in an operative position by a detent means which includes a spring-closed relief valve 39 slidably disposed in an enlarged bore-like extension 37a of the longitudinal passage 37 and normally disposed to close the right end of said passage. Said relief valve is connected by a transverse pin 40 to a sleeve 41 slidably disposed in the right end of the bore 34, while a sleeve-like piston extension 35d, having slots 42 therein for accommodating said pin, is telescoped for slidable movement between the relief valve and the sleeve 41. A helical spring 43 compressibly disposed between the right end of relief valve 39 and a transverse pin 44 extending throughthe sleeve 35d and into a sleeve 45 surrounding the latter, normally holds said relief valve in a closed position. In this closed position the two sleeves 41 and 45 being slightly separated provide an axial gap 46 therebetween that may be brought into registration with a garter-like detent spring 47 that is positioned in an annular groove 48 and which snaps into the gap and holds the piston 35 in position against the restoring force or reaction of a centering spring 49 when said piston is moved to the right. The centering spring 49 is compressibly positioned between a flange 50, on collar 51, and a washer 52 slidably mounted on sleeve 45 and normally engaging the edge of an end closure cap 53. The collar 51 is slidably mounted by means of a flange 54 on the sleeve 45, while its axial movement is limited by a split ring 55 carried by said latter sleeve, and, as shown in Figure 2, said flange abuts said ring thereby normally urging the sleeve 45, the sleeve 35d and the valve piston 35 to the left. When said valve piston is displaced out of neutral position, such, for instance, as by a movement thereof to the left, the washer 52, being urged to follow the piston by a retaining ring 56, will compress the centering spring 49 against the flange 50 while said latter flange, in turn, is pressed against a shoulder 57 at the end of bore 3-4 in the valve body.

In actuating the control valve the operator has only to shift the handle 28, in the direction corresponding to themovement desired for the ram piston, and then release it, whereupon the detent spring 47 by contracting into the gap 46 when the piston moves to the right serves to retain the valve piston in position until completion of the ram piston movement, after which the valve piston will automatically return to its neutral position. Assume, for instance, that the handle 28 is shifted to the left, to eifect contraction of the ram unit, in which case the valve piston 35 will move to the right from that shown in Figure 2 to that seen in Figure 3. JIhen when the ram piston moves a distance corresponding with the depth determined by a presetting of the depth control valve 12 (as hereinafter described) the fluid flow is substantially restricted, because of operation of said latter valve, whereupon the pressure immediately rises in the inlet port 29 and in the passage 37 to the predetermined value which is necessary to overcome the relief valve spring 43 and open said relief valve (Figure 4) to effect discharge of fluid through radial port 53 into a passage 59 that leads back to the outlet or return port 30. The opening movement of the relief valve 39' carries the interconnected sleeve 41 to the right, closing the gap 46 and displacing the detent spring 47 therefrom, after which said detent spring engages the smooth surfaces of the abutting sleeves 41 and and permits the valve piston 35 to be urged back to neutral by the centering spring 49. This return movement of piston 35 causes the inlet pressure port 29 to be reconnected with the return or discharge port 30 thereby releasing the pressure of the fluid whereupon the relief valve 39 closes, and the attendant movement of the sleeve 41 away from sleeve 45 restores the gap 46 and re-positions the lands 35a and 35b to block olf the'work ports 31 and 32. 7

When the valve piston 35 is moved to the left, in order to transmit fluid pressure into the lower end of the ram unit, a detent spring 60 is brought into registration and engagement with the gap 46 to retain the position of said valve piston until the ram piston has completed its longitudinal movement, after which the pressure in the passage 37 again rises and the relief valve 39 is opened and the sleeve 41 is brought into closely abutting contact with the sleeve 45 to close the gap 46 and displace the detent spring 60 therefrom, whence the centering spring 49 again restores the valve piston to its neutral position.

While the preceding, by way of example, describes one specific pressure release valve of the type that may be used with the present invention it should be understood that its use is not limited to the particular valve shown and described. Another valve of this type which is particularly adaptable for use with the present invention is shown and described in the pending U.S. patent application Serial No. 526,050, filed August 2,1955, now US. Patent 2,836,195.

Now in accordance with the specific teachings of the present invention there is provided the combination indicator and adjustable cut-off or restrictor valve mechanism indicated generally by the reference numeral 12. This unit comprises a body or casing member 61 having oppositely extending port openings 62 and 63 therein, connected, respectively, with the conduits 11 and 15, and a centrally disposed vertical bore 64 extending through the body slidably accommodating a hollow captivated tubular member 65. This tubular member extends outwardly from one end of said bore, while a closure member 66 positioned to cover the'opposite end of the bore may be aflixed to the body 61, by suitable fastening means such as the screws 67. An enlarged bore portion 64a extending axially inwardly from one end of the bore 64 receives a helical spring 68 which is compressibly positioned between a shoulder 69, in the bore 640, and a split ring 70 mounted in an annular groove 71 provided in the outer surface of the tube 65 proximate one end thereof. Conventional sealing rings, such as indicated at 72 and 73, may be provided for appropriately containing the fluid pressure Within the body 61.

The ports 62 and 63 are connected with the central bore 64 by passages 74 and 75, respectively, which open thereinto, and an annular groove 76 in the tubular member 65 is disposed to be registerable in overlapping relation with said port opening passages. It will be noted that the axial length of the annular groove 76 is slightly greater than the diameter of the port openings in passages .74 and and that the land 77 on the tubular valve memher 65 never completely covers or blocks ofi the openings of passages 74 and 75 when the tubular valve is in its fully operated position (Figure 6). This arrangement is provided so as to permit leakage of a small quantity of fluid through the valve so that when it is desired at some subsequent time to move the ram unit in the opposite direction it will not be hydraulically blocked, as will be more fully explained hereinafter.

The captivated tube 65 is provided with a longitudinally extending slotted opening 78 that is adapted to receive a pointer 79 slidably disposed therewfthin for movement therealong. The pointer is fashioned with a transverse pin member 80 that extends through the slotted opening 78 and is slidably mounted therewithin by the oppositely positioned brackets 81 and 82 (Figure 5). Each of these brackets is generally U-shaped in cross-section, and the center or the connecting leg of each is suitably secured to the pin 80 while the parallel, spaced apart arms thereof straddle the inner and outer walls adjoining the sides of the slotted opening 78, of the tube 65, so that the pointer is free to slide along the opening without being accidentally displaced therefrom. The outer surface of the tube 65 is provided adjacent the slot 78 with indicia markings or scale graduations 83 which may be accurately correlated with the depth at which the ground working implement is to be operated, or, if desired, they may be merely graduations to indicate relative up and down or vertical positions of the implement.

A collar member 84 fitted over the outer diameter of the tube 65 is dimensioned for slidable movement therealong, while a manually operable adjusting screw 85 therein permits the collar to be moved and fixedly repositoned at any particular setting desired along the graduated scale.

The pointer pin 80 is engaged for movement by one end of a plunger or connecting rod 86, dimensioned for slidable movement axially within the tube 65, while the opposite end of said plunger has an axially extending opening therein that receives one end of a small dameter wire 87 of the well known Bowden type that may be fixedly secured in place therewithin, by suitable means such as the set screw 88.

Wire 87 is enclosed within a flexible but semi-rigid sheath-like conduit 89, fashoned of any suitable well known plastic sheathing or covering material, and extends outwardly through an opening 90 in the cap closure member 66. The closure 66 may be fashioned with a shoulder or shelf-like portion 91 to which a U-shaped clamp 92 may be secured by screws 93 to fixedly anchor one end of conduit 89 and prevent lateral displacement of the wire 87 enclosed therewithin. The opposte end of wire 87 is rigidly afiixed to one end of a slidable connecting rod 94 having a ring-like eyelet 95 on the opposite end thereof, which eyelet is adapted for mounting over the pin 26a, in the drawbar linkage (not shown), and that mountably receives the lug 26 on one end of the ram piston rod 25. A section of rigid conduit or tubing 96, fitted over the rod 94 and its attached wire, overlaps one end of the flexible conduit 89, and a packing gland nut 97 threaded on the open proximate end of said rigid conduit may be provided for retaining any suitable well known bushing or sealer, such as the packing material indicated at 98, therewithin. Afixed, as by welding or the like, proximate opposite ends of the conduit 96 are strap fasteners 99 and 108 which serve together with the cap screws 101 and 192, respectively, to fixedly anchor or position said conduit on the housing of the ram unit 10. Suitable additional clamps may be provided, as desired, for mounting other portions of the flexible conuit 89 on the vehicle body or chassis as the particular needs dictate, all as is well understood.

In operating the present invention the operator first selects the depth at which the ground working implement is to be operated, and then sets the adjustable collar 84 at the proper corresponding location on the scale 83 to provide the desired depth of implement operation. Next the handle 28 of the control valve '14 is moved or rotated to the left, as viewed in Figures 1-3, moving the piston 35 thereof to the right to efiect the introduction of fluid pressure, by way of ports 29 and 32, conduit 15, and port 63, into the depth control cut-ofi valve 12. Since the implement is assumed at this time to be in its raised position the ram piston 24 will be extended, and the position sensing wire 87, following the motion of the piston, will have moved the pointer 7 9 to the bottom of the slot 78 in the captivated tube 65. Under this condition the biasing spring 68 will effectively maintain the tube 65 pressed down against the closure cap 66 thereby providing free communication or flow of fluid pressure through the passages 75 and 74 and, by way of conduit 11, into the upper end of ram cylinder 21 to initiate the movement of contracting the ram unit it When the ram unit has contracted sufficiently, to provide the working depth desired for the associated ground working implement, the plunger rod 86, being moved by the Bowden wire 87, forces the pointer 79 into engaging contact with the previously set collar 84. Further movement of the ram unit then will cause the pointer 79 to press against collar 84 with suflicient force to raise the captivated tube 65 upwardly against the reactive force of spring 68, thereby raising the land 77 of said valve into position to start blocking or partially covering the openings in passages 74 and 75 and, in so doing, restricting the flow of fluid pressure therethrough. As the opening through the valve 12 is thus restricted pressure in the conduit 15 starts rising and when it has risen suflicien-tly it operates the relief valve component 39, in control valve 14, as previously explained, and this, in turn, then operates to trigger the release and return to neutral of the control valve 14, which action simultaneously discontinues the flow of fluid pressure into the ram unit 12.

When the operator desires to raise the implement from a previous ground working depth position the handle 28, of control valve 14, is rotated to the right with the result, as previously explained, that fluid pressure is directed by way of conduit 13 into the lower end of ram cylinder 21. As the piston in the ram unit rises the fluid forced out of the opposite end of the cylinder flows by way of conduit 11, valve 12, and conduit 15 back to control valve 14 from whence it enters the reservoir 17. Since the shut-off valve 12 is so arranged that, in its fully operative position, it only restricts and does not completely cut-01f the flow of fluid pressure therethrough, it will be appreciated that as soon as the ram piston starts its movement in the cylinder fluid may flow out of the upper end of the ram cylinder and back through valves 12 and 14 into the reservoir 17. Attendant this movement of ram piston 24 the wire 87 follows and initiates movement of pointer 79 away :from collar 84 which, when such pressure is removed, permits the tube 65 by virtue of the reaction of spring 68, to be lowered until the land 77 thereon ultimately clears the openings of passages 74 and 75 and reestablishes the free flow of fluid pressure therethrough.

While only one form of the invention has been shown, it will be obvious to those skilled in the art that it 'is not so limited, but is susceptible of various changes and modifications Without departing from the spirit thereof, and it is desired, therefore, that only such limitation shall be placed thereon as are specifically set forth in the appended claims.

What is claimed is:

1. In a hydraulic system having a hydraulic ram unit having a hydraulically actuated movable element'therein operative for raising and lowering a ground working implement associated therewith, a 'restrictor valve, comprising: a casing fixed in said system and remotely disposed relative to said ram unit and formed with a bore therethrough and having port openings in the casing communicating with said bore and adapted for connection into the hydraulic system for admitting hydraulic fluid to said ram unit, and a plunger slidably disposed in said bore and operative for Conditioning the restrictor valve in one position thereof to permit the free flow of fluid pressure therethrough and in another position for restricting the fiow of fluid pressure therethrough, stop means adjustably affixed at any of a plurality of presettable stop positions to the exterior of said valve plunger and engageable for sliding said plunger from the position of free flow to the restricted flow position thereof, wire control means flexibly connectable between the ram unit and said stop means and operably'responsive to movement of the movable ram element for engaging said stop means according to the preset position thereof and thereafter sliding said valve plunger to a position so as to condition said restrictor valve means for restrictive fluid flow therethrough.

2. In a hydraulic system having a hydraulic ram unit having a hydraulically actuated movable element therein operative for raising and lowering a ground working implement associated therewith, a restrictor valve, comprising: a casing fixed in said system and remotely disposed relative to said ram unit and formed with a bore therethrough and having port openings in the casing communicating with said bore and adapted for cormection into the hydraulic system for admitting hydraulic fluid to said ram unit, and a plunger slidably disposed in said bore and operative for conditioning the restrictor valve in one position thereof to permit the free flow of fluid pressure therethrough and in another position for restricting the flow of fluid pressure therethrough, stop means removably aflixed to the exterior of said valve plunger at any one of a plurality of presettable positions therealong, said stop means being engageable for slidably actuating said valve plunger and conditioning said restrictor valve for restricted flow therethrough, movement control means flexibly connected between the ram unit and said restrictor valve and having one end of said means connected for movement with the movable element of the ram unit while the other end thereof is disposed for engaging said stop means, the presettable positions on said'valve plunger being correlated to positions of the movable element of the ram unit so that the point of engagement of said stop means and the subsequent actuation of said resistor valve is determined by the respective position of the movable element of the ram unit.

3. A restrictor valve for use in a hydraulic system including, an interconnected source of fluid pressure, and a hydraulic ram unit with a movable element therein operative responsive to the flow of fluid pressure in the system and operative for raising and lowering an associated ground working implement and having a connecting rod means associated therewith that is operably responsive to movement of the movable element thereof, and wherein the introduction of a restriction of fluid flow in the system is operative to interrupt the flow of fluid pressure from the source of pressure to the ram unit so as to stop the raising and lowering operation of the ram unit, comprising: a body fixed with respect to said system and remotely disposed relative to said ram -unit'and having a bore therethrough and port passages communicating with said bore and adapted for connection into the" hydraulic system for admitting hydraulic fluid to said ram, and a valve spool slidably disposed in said bore and extending outwardly beyond one end thereof and having an annular groove thereon registrable with the port passages of said body to permit the free flow of fluid pressure therethrough; yieldable means normally urging said valve spool into position for registering the annular groove thereon with said port passages; stop means adjustably aflixable to the outwardly extending end of said spool; motion transmitting means connece 8 able with the connecting rod means of said ram unit for movement therewith and'engageable with said stop means for sliding said spool into position so as to etfect only partial registration of the annular groove thereof with said port passages and thereby condition said restrictor valve for restricted fluid flow therethrough.

4. A restrictor valve for use in a hydraulic system including, an interconnected source of fluid pressure, and a hydraulic ram unit with a movable element therein operative responsive to the flow of fluid pressure in the system and operative for raising and lowering an associated ground working implement and having a connecting rod means associated therewith that is operably re sponsive to movement of the movable element thereof, and wherein the introduction of a restriction to fluid flow in the system is operative to interrupt the fiow of fluid pressure from the source of pressure to the ram unit so as to stop the raising and lowering operation of the ram unit, comprising: a body fixed with respect to said system and remotely disposed relative to said ram unit and having a bore therethrough and port passages in the body communicating with said bore and adapted for connection into the hydraulic system for admitting hydraulic fluid to said ram unit, and a hollow valve element slidably disposed in said bore and extending outwardly beyond one end thereof and having a passage defining annular groove registerable with said port passages to permit the unrestricted flow of fluid pressure therethrough; yieldable means mounted in said body normally urging the hollow valve element into position for permitting the unrestricted flow of fluid pressure therethrough; limit means adjustably affixable to said valve element in any one of a plurality of selected positions; motion transmitting means connectable with the connecting rod means of said unit for movement therewith and including a 'movable element engaging means slidably mounted in said hollow valve element and engageable with said limit means upon movement of the movable element of the ram in one direction to effect the sliding of said hollow valve element into position wherein said annular groove only partially registers with said port passages so that said restrictor valve is conditioned for restricted fluid flow therethrough.

5. A restrictor valve for use in a hydraulic system including, an interconnected source of fluid pressure, and a hydraulic ram unit with a movable element therein operative responsive to the flow of fluid pressure in the system and operative for raising and lowering an associated ground working implement and having a connecting rod means associated therewith that is operably responsive to movement of the movable element thereof and wherein the introduction of a restriction to fluid flow in the system is operative to interrupt the flow of fluid pressure from the source of pressure to the ram unit so as to stop the raising and lowering operation of the ram unit; comprising: a body fixed with respect to said system and remotely disposed relative to said ram unit and having a bore therethrough and port passages in the body communicating with said bore and adapted for connection into the hydraulic system for admitting hydraulic fluid to said ram unit, and a hollow valve element slidably disposed in said bore and extending outwardly beyond one end thereof and having a passage defining annular groove registerable with said port passages to permit the unrestricted flow of fluid pressure therethrough; yieldable means mounted in said body nor mally urging the hollow valve element into position for permitting the unrestricted flow of fluid pressure therethrough; said hollow valve element having a longitudinally extending slotted opening therein with scale markings therealong; pointer means slidably mounted in said slot for movement therealong and extending into the hollow portion of said hollow valve element; stop means adjustably aflixed to said hollow element in the vicinity of any one of the scale markings therealong and dis- 9 posed to limit the movement of said pointer means; movement transmitting means connectable' with the connecting rod means of said ram unit for movement there with and including a movable element slid-ably disposed within said hollow valve element and engageable with said pointer means and operative for bringing said pointer into engagement with said stop means upon movement of the movable element of the ram in one direction and thereafter sliding said hollow valve element into position such that the annular groove therein only partially registers with said port passages so that the flow of fluid pressure therethrough is restricted.

6. A restrictor valve for use in a hydraulic system including, an interconnected source of fluid pressure, and a hydraulic ram unit with a movable element therein operative responsive to the flow of fluid pressure in the system and operative for raising and lowering an associated ground Working implement and having a connecting rod means associated therewith that is operably responsive to movement of the movable element thereof, and wherein the introduction of a restriction to fluid flow in the system is operative to interrupt the flow of fluid pressure from the source of pressure to the ram unit so as to stop the raising and lowering operation of the ram unit, comprising: a body fixed with respect to said system and remotely disposed relative to said ram unit and having a bore therethrough and port passages in the body communicating with said bore and adapted for connection into the hydraulic system for admitting hydraulic fluid to said ram unit, and a hollow valve element slidably disposed in said bore and extending outwardly beyond one end thereof and having a passage defining annular groove registerable with said port passages to permit the unrestricted flow of fluid pressure therethrough; said body having a closure member disposed to cover the open end of said bore; yieldable means compressibly mounted between said body and said hollow valve element urging said latter element normally into engagement with said cover and into position for permitting the unrestricted flow of fluid pressure through the restrictor valve; said hollow valve element having a longitudinally extending slotted opening therein with scale gaduations therealong; pointer means slidably mounted for movement along said slotted opening and extending therethrough into the hollow portion of said valve element; stop means including a collar slidably mounted on the exterior of said hollow valve element and adjustably aflixable thereto in the vicinity of any one of the scale graduations therealong and disposed for limiting the slidable movement of said pointer means; movement transmitting means connectable with the connecting rod means of said ram unit for movement therewith and including a plunger element slidably positioned within said hollow valve element and disposed for engagement with said pointer means and operative for bringing said pointer into engaging relation with said stop means upon movement of the movable element of said ram in one direction and thereafter sliding said hollow valve element into position such that the annular groove therein only partially registers with said port passages so that the flow of fluid pressure therethrough is restricted.

7. In a hydraulic system having a hydraulic ram unit therein, a restrictor valve, comprising: a body fixed in said system and remotely disposed with respect to said hydraulic ram and having a bore therethrough and port passages communicating with said bore and adapted for connection into the hydraulic system for admitting hydraulic fluid to said ram unit, a valve spool slidably disposed in said bore and extending outwardly beyond one end thereof and having an annular groove thereon registerable with the port passages of said body to permit the free flow of hydraulic fluid through the valve, yieldable means normally urging said spool into position for registering the annular groove thereon with said port passages, stop means adjustably aflixable to the outwardly extending end of said spool, movement transmitting means connectable with said ram unit and operative for transmitting movements of the hydraulic ram to the restrictor valve, said movement transmitting means being arranged for engaging said stop means and thereafter sliding said spool into position so as to eflect only partial registration of the annular groove thereof with said port passages and thereby condition the valve for re stricted fluid flow therethrough.

8. In a hydraulic system having a hydraulic ram unit therein, a restrictor valve, comprising: a body fixed in said system and remotely disposed with respect to said hydraulic ram and having a bore therethrough and port passages communicating with said bore and adapted for connection into the hydraulic system for admitting hydraulic fluid to said ram unit, a hollow valve element slidably disposed in said bore and extending outwardly beyond one end thereof and having a passage defining annular groove registerable with said port passages to permit the unrestricted flow of hydraulic fluid through the valve, yieldable means compressibly mounted between said body and said hollow valve element urging said latter element normally into position for permitting the flow of hydraulic fluid through the valve, said hollow valve element having a longitudinally extending slotted opening therein with scale graduations therealong, pointer means slidably mounted for movement along said slotted opening and extending therethrough into the hollow portion of said hollow valve element, stop means including a collar slidably mounted on the exterior of said hollow valve element and adjustably afiixable thereto in the vicinity of any one of the scale graduations therealong and disposed for limiting the slidable movement of said pointer means, movement transmitting means for transmitting movements of the hydraulic ram to the restrictor valve including a plunger element slidably positioned within said hollow valve element and disposed for engagement with said pointer means and a wire control means flexibly connectable between said plunger element and the hydraulic ram unit and operative upon movement of said ram unit for bringing said pointer means into engaging relation with said stop means and thereafter sliding said hollow valve element into position such that the annular groove therein only partially registers with said port passages so as to condition said valve for restricted fluid flow therethrough.

9. In a hydraulic system having a hydraulic ram unit therein, a restrictor valve, comprising: a body fixed in said system and remotely disposed with respect to said hydraulic ram and having a bore therethrough and port passages communicating with said bore and adapted for connection into the hydraulic system for admitting hydraulic fluid to said ram unit, a hollow valve element slidably disposed in said bore and extending outwardly beyond one end thereof and having a passage defining annular groove registerable with said port passages to permit the unrestricted flow of hydraulic fluid through the valve, yieldable means compressibly mounted between said body and said hollow valve element urging said latter element normally into position for permitting relatively unrestricted flow of hydraulic fluid through the valve, said hollow valve element having a longitudinally extending slotted opening therein with scale graduations therealong, pointer means slidably mounted for movement along said slotted opening and extending therethrough into the hollow portion of said hollow valve element, stop means including a collar slidably mounted on the exterior of said hollow valve element and adjustably aflixable thereto in the vicinity of any one of the scale graduations therealong and disposed for limiting the slidable movement of said pointer means in one direction, movement transmitting means for transmitting movements of the hydraulic ram to the restrictor valve,

11 said movement transmitting means including a movable element slidably disposed within said hollow valve element and engageable when moved in one direction with said pointer means and a wire control means flexibly connectable between said movable element and the hy- 5 draulic ram unit, said movement transmitting means 1'2 passages and thereby condition the valve for restricted fluid flow therethrough.

References Cited in the file of this patent UNITED STATES PATENTS 2,547,861 Fletcher Apr. 3, 1951 2,591,492 Anderson Apr. 1, 1952 2,594,664 Livers Apr. 29, 1952 2,606,414 Dyrr Aug. 12, 1952 2,614,537 Starr Oct. 21, 1952 2,615,430 Fletcher Oct. 28, 1952 2,670,713 Jirsa Mar. 2, 1954 

